JP2002196574A - Developing device and image forming device - Google Patents

Abstract

(57) [PROBLEMS] To supply a necessary and sufficient developer to a developing chamber and a developer carrying member without packing of the developer in a developing chamber. SOLUTION: A developing chamber 3 having a developer carrier 1 for transporting the developer to an image carrier 2 is accommodated, and the developer chamber 3 or an adjacent hopper chamber 5 is stirred while the developer is stirred.
At least two or more hopper chambers 5 and 7 having rotary stirring members 6 and 8 for transporting the developer to the developing chamber 3 and the hopper chambers 5 and 7 are all communicated with each other and partitioned by partitions. In the developing device, a partition wall 10 between two adjacent hopper chambers 5 and 7 is connected to the upstream hopper chamber 7 for transporting the developer from the hopper chamber 7 on the upstream side in the developer transport direction to the hopper chamber 5 on the downstream side. Is a wall-shaped partition having a height lower than the rotation center of the rotary stirring member 8 in the inside, and a partition wall 9 between the developing chamber 3 and the hopper chamber 5 has a slit-shaped opening 9a in one wall. It is characterized by having a partition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing using a developer, and more particularly to a developing device used for an image forming apparatus such as a copying machine or a printer using an electrophotographic recording system.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic recording method, such as an electrophotographic copying machine or an electrophotographic printer, uniformly charges an electrophotographic photosensitive member, and then performs exposure in accordance with image information to perform static exposure. An electrostatic latent image is formed, and then a developer is attached to the latent image by a developing unit to form a visible image (toner image). Thereafter, the toner image is transferred and fixed on a recording medium to obtain an image.

In such an apparatus, an electrophotographic photosensitive member, a charging unit, a developing unit, a cleaning unit, and the like are collectively formed into a cartridge into a cartridge, so that a user himself can attach the process cartridge to an image forming apparatus main body. A device that is easy to maintain by being replaceable has been put to practical use.

In recent years, however, attention has been paid to a process cartridge or a developing device of a type which replenishes toner with respect to a process cartridge type, because the unit has a short service life and replacement of each unit increases costs. I have. Further, in a developing device of a type that replenishes toner, the replenishment interval is lengthened in order to reduce the number of replenishment operations by the user. Therefore, the amount of toner replenishment at one time is large.

Generally, a developing device is arranged around an electrophotographic photosensitive member on which an electrostatic latent image is formed by a charging device and exposure means. The developing device carries a developer on its surface, transports the developer to a development area, and develops an electrostatic latent image on the electrophotographic photoreceptor, and a developer carried on the developer carrier. A developer chamber for accommodating a developer regulating member for forming a layer to a predetermined thickness, etc., for accommodating the developer,
A hopper chamber having a stirring member for conveying the developer to the developing chamber while stirring the developer, a remaining amount detecting member for detecting the remaining amount of the developer in the developing device, and the like are arranged.

[0006] Usually, in the developing device, a developer carrying member is arranged so as to substantially close a developer discharging port of the developing container containing the developer in the vicinity of the electrophotographic photosensitive member. The inside of the developing device is divided into a developing chamber including a developer carrier and one or more other hopper chambers. Further, in the developing chamber, the developer is frequently stirred in order to transport more developer to the developer carrier, so that the developer is greatly deteriorated. Therefore, when a large amount of the developer is transported to the developing chamber, the large amount of the developer is deteriorated in a short time.

Further, the developing device of the type which replenishes toner has a developer remaining amount detecting member, which detects when the remaining amount of the developer has decreased to a predetermined amount, and informs the user of developing. An operation to prompt the supply of the medicine is performed. Particularly, in a developing device in which the life of the developing device is long and the developer is supplied, it is important to accurately detect the remaining amount of the developer. If the amount of developer is too large, packing may occur due to excessive developer in the developing chamber, causing deterioration of the developer, or the residual developer may be removed when new developer is supplied. Problems such as abnormal charging of the developer due to mixing of the new developer occur.

Various methods have been proposed for detecting the remaining amount of the developer. One of the most common methods is a method using a piezo element. In this method, the state where the developer is present on the sensor surface and the state where the developer is not present are detected. The sensor is disposed such that the sensor surface is exposed on the inner wall of the developing chamber or the hopper chamber, and the remaining amount of the developer is detected. Developing room,
When there are a plurality of hopper chambers, the remaining amount of the developer is detected by arranging a developer remaining amount detecting member in one of the developing chambers or the hopper chamber.

[0009]

A conventional example will be described with reference to FIG. FIG. 5 is a schematic sectional view of a collectively replenishing type developing device.

The developer carrier 101 is rotated in the direction of the arrow, and a developer layer is formed on the surface of the developer carrier by the developer regulating member 111. The developer is conveyed to the developer carrier 101 at a position facing the image carrier 102. Developing. A developing chamber 103 is arranged adjacent to the developer carrying member 101, and the developer carrying member 101
The developer is supplied to the developer carrier 101 by a stirring member 104 in the developing chamber that transports the developer to the developer carrier 101 while stirring the developer along the longitudinal direction of the developer. A first hopper chamber 105 is adjacent to the developing chamber 103 via a partition wall 109. This first hopper chamber 105
Is provided with a first rotary stirring member 106 which transports the developer toward the developing chamber 103 while stirring the developer. Further, a second hopper chamber 107 is adjacent to the first hopper chamber 105 via a partition wall 110. The second hopper chamber 107 is filled with the first hopper chamber 1 while stirring the developer.
A second rotary agitating member 108 that conveys the toner toward the section 05 is provided. In addition, an opening 112 that can be opened and closed for replenishing the developer is provided in the upper part of the developing device.

The stirring member 104, the first rotation stirring member 106, and the second rotation stirring member 108 rotate at a fixed ratio to the rotation speed of the developer carrier 101, respectively. Stir and transport.

When the developer is supplied, the supplied developer is supplied to the first rotation stirring member 106 and the second rotation stirring member 1.
At the same time, the developer is conveyed in the direction of the developing chamber 103.

Here, the partition wall 109 and the partition wall 110
Is lower than the center of rotation of the first rotary stirring member 6 and the second rotary stirring member 8, respectively, the developer easily passes over the partition walls 109 and 110 and the developing chamber 10
3, immediately after replenishment of the developer or in a state where a large amount of the developer is present in the first hopper chamber 105 and the second hopper chamber 107, a large amount of the developer is fed into the developing chamber 103, and Packing of the developer in the room occurs, causing problems such as deterioration of the developer, poor coating of the developer on the developer carrier, and a resulting decrease in the development density.

When the height of the partition wall 109 and the height of the partition wall 110 are higher than the rotation centers of the first rotary stirring member 106 and the second rotary stirring member 108, respectively, the developer is supplied to the partition wall 109 and the partition wall 110. Is not used in each hopper chamber, and the amount of remaining developer that deteriorates without being used increases, causing waste of developer and an increase in the amount of remaining developer in the entire developing device when the developer is supplied. Occurs.

Further, the supply of the developer to the developing chamber 103 cannot be carried out smoothly, so that a defect such as a defective coating of the developer on the developer carrying member due to a shortage of the developer and an image white spot due to the defect occur.

Further, in the developing chamber 103, a developer remaining amount detecting member 113 is disposed so as to be centered at a position on the near side of the inner wall of the developing chamber and about 15 mm from the bottom of the developing container. The developer remaining amount detecting member 113 is configured by a piezoelectric element, and detects the presence or absence of the developer in a portion immediately before the developer remaining amount detecting member 113 inside the developing chamber 103, and
The detection signal is transmitted to the developer remaining amount determination device 114. The developer remaining amount determining device 114 continuously receives a signal from the developer remaining amount detecting member 113 and
At the point in time when a developer-less signal is received from 13, it is determined that there is no developer. The sensor surface of the developer remaining amount detecting member 113 has a circular shape with a diameter of about 10 mm, and the developer is present in all regions on the sensor surface from the case where the developer is not present in more than 1/2 region on the sensor surface. A signal indicating that there is no developer is output in one of the states where no developer exists. That is, from the state where the amount of the developer is reduced to the line a in FIG.
The output of the signal indicating that there is no developer is started while the developer is in a state where the developer has decreased. Therefore, when it is determined that there is no developer, the amount of the remaining developer in the developing container fluctuates between the line a and the line b, which is an error range.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to prevent the developer from being packed in the developing chamber and to reduce the amount of the developing chamber and the developer carrying member. It is to supply a necessary and sufficient developer.

A second object is to perform high-precision detection at the time of replenishment of the developer, at the same time leave sufficient developer to be supplied to the developer carrier, and minimize the total amount of the remaining developer. It is to limit.

[0019]

In order to achieve the above object, a typical configuration of the present invention is to provide a developing chamber having a developer carrier for transporting a developer to an image carrier, a developer chamber, At least two or more hopper chambers having a rotary stirring member for transporting the developer to the developing chamber or an adjacent hopper chamber while stirring the developer, and the developing chamber and the hopper chamber are all communicated with each other. In the developing device, the partition between the two adjacent hopper chambers is formed by rotating and stirring the upstream hopper chamber for transporting the developer from the upstream hopper chamber to the downstream hopper chamber in the developer transport direction. The partition is a wall-shaped partition having a height lower than the center of rotation of the member, and the partition between the developing chamber and the hopper chamber is a partition having a slit-shaped opening in a wall on one surface. .

According to the above configuration, packing of the developer in the developing chamber does not occur, and the necessary and sufficient developer can be supplied to the developing chamber and the developer carrier.

Further, in the developing chamber or the hopper chamber,
By providing at least one developer remaining amount detection member, highly accurate detection can be performed at the time of replenishment of the developer, and at the same time, sufficient developer is left to be supplied to the developer carrier. It is possible to minimize the amount of residual developer.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However,
The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions, and in particular, Unless otherwise described, the scope of the present invention is not intended to be limited to them.

[First Embodiment] An image forming apparatus provided with a developing device to which the present invention is applied will be described with reference to the drawings. First, an image forming apparatus provided with a developing device according to the present invention will be described with reference to FIG.
The developing device according to the embodiment will be described.

FIG. 2 is a schematic structural view showing a schematic structure of an image forming apparatus provided with a developing device according to the present invention. In FIG. 2, reference numeral 2 denotes an image carrier such as a photosensitive drum, the surface of which is uniformly charged by a charging unit 22. Then, the surface of the image carrier 2 uniformly charged by the charging unit 22 is irradiated with an image exposure corresponding to an image signal (for example, an input original image or the like) from the exposure unit 23 to thereby form the image carrier 2. An electrostatic latent image is formed on the surface. After the electrostatic latent image is developed into a toner image by a developing device 24 to be described later, the toner image on the image carrier 2 is transferred by a transfer unit 25 to a recording medium fed at the same timing as the toner image. Transcribe. After the transfer, the toner remaining on the image carrier 2 is removed by the cleaning unit 26. The recording medium to which the toner image has been transferred as described above is sent to a fixing unit 27 via a guide or the like, and after the fixing unit 27 fixes the toner image, the recording medium is discharged. In the drawing, reference numeral 28 denotes a recording medium transport path.

Next, the developing device in the image forming apparatus will be described in detail with reference to FIG. FIG. 1 is a schematic sectional view of a developing device according to the first embodiment of the present invention.

As shown in FIG. 1, the developer carrier 1 is rotating in the direction of the arrow, a developer layer is formed on the surface thereof by the developer regulating member 11, and the developer is conveyed to the image carrier. Development is performed at a position facing the body 2. Developer carrier 1
A developer chamber 3 is disposed adjacent to the developer carrier 1, and the developer is supplied to the developer carrier 1 by a developing chamber stirring member 4 that transports the developer while stirring the developer along the longitudinal direction of the developer carrier 1. Have been done.

The first hopper chamber 5 is adjacent to the developing chamber 3 via a partition wall 9. In the present embodiment, the partition wall 9 is a wall on one surface from the bottom to the upper lid of the developing container, and has a configuration in which a slit-shaped opening 9a having a width of 5 mm is opened in the entire longitudinal direction. ing.

The first hopper chamber 5 is provided with a first rotary stirring member 6 for transporting the developer toward the developing chamber 3 while stirring the developer, and a slit-shaped opening 9 of the partition wall 9 is provided.
The developer is supplied to the developing chamber 3 through “a”.

Further, the first hopper chamber 5 has a partition wall 1.
The second hopper chamber 7 is adjacent via a zero. The partition wall 10 is a wall-shaped partition having a height lower than the rotation center of the second rotary stirring member 8 in the second hopper chamber 7.

In the second hopper chamber 7, a second rotary stirring member 8 for transporting the developer toward the first hopper chamber 5 while stirring the developer is arranged. An opening 12 that can be opened and closed for replenishing the developer is provided in the upper part of the developing device.

In this embodiment, the center of rotation of the first rotary stirring member 6 and the second rotary stirring member 8 is about 5 mm from the bottom of the developing container.
This is the position of 0 mm. The slit-shaped opening width of the partition wall 9 is about 5 mm, and is located at a height of 20 mm from the bottom of the developing container. The height of the partition wall 10 is 30 mm from the bottom of the developing container.

The present invention is not limited to the above numerical values. For example, if the height of the slit-shaped opening 9 a of the partition wall 9 between the developing chamber 3 and the first hopper chamber 5 is lower than the rotation center of the first rotary stirring member 6 in the first hopper chamber 5. In addition, the height of the partition wall 10 between the adjacent hopper chambers 5 and 7 may be lower than the height of the rotation center of the second rotary stirring member 8 in the second hopper chamber 7.

The developer supplied from the opening 12 in the upper portion of the developing container is conveyed from the second hopper chamber 7 to the first hopper chamber 5 and from the first hopper chamber 5 to the developing chamber 3. Since the height of the partition wall 10 is lower than the rotation center of the second rotary stirring member 8 as described above, the developer swept up by the second rotary stirring member 8 in the second hopper chamber 7 is , Easily passes over the partition wall 10 and is transported to the first hopper chamber 5. Further, when the developer is present at a height higher than the height of the partition wall 10, the second rotary stirring member 8
As a result, a part of the developer transported to the first hopper chamber 5 returns to the second hopper chamber 7 so that the remaining developer amount in the first hopper chamber 5 and the second hopper chamber 7 becomes the same. Also, packing of the developer due to excessive transport of the developer does not occur. When the developer is less than the height of the partition wall 10, the developer transported to the first hopper chamber 5 by the second rotary stirring member 8 passes over the partition wall 10 and returns to the second hopper chamber 7. You can't do that
It is possible to reduce the remaining developer amount in the hopper chamber 7.

Since the developer is supplied from the first hopper chamber 5 to the developing chamber 3 through the above-described slit-shaped opening having a width of about 5 mm, the developer is supplied little by little. No packing or abnormal charging occurs.

Further, in the developing chamber 3, a developer remaining amount detecting member 13 is disposed such that a position about 15 mm from the bottom of the developing container is located on the near side of the inner wall of the developing chamber.

The developer remaining amount detecting member 13 is constituted by a piezoelectric element, which detects the presence or absence of the developer in a portion immediately before the developer remaining amount detecting member 13 inside the developing chamber 3, and The detection signal is transmitted to the developer remaining amount determination device 14. The developer remaining amount determination device 14 continuously receives a signal from the developer remaining amount detecting member 13, and determines that there is no developer when the developer remaining amount detecting member 13 receives a developer absence signal from the developer remaining amount detecting member 13. . The sensor surface of the developer remaining amount detecting member 13 has a circular shape with a diameter of 10 mm, and the developer is present in all regions on the sensor surface since the developer is not present in a half or more region on the sensor surface. A signal indicating that there is no developer is output in one of the states where no developer exists. That is, the output of the no-developer signal is started during the period from the state where the amount of the developer is reduced to the line a in FIG. 1 to the state where the amount of the developer is reduced to the line b.

The user is prompted to supply the developer to the developing device based on the signal indicating that the developer is not used. Specifically, for example, although not shown, the fact is displayed on a display unit or the like of an operation panel on the upper surface of the apparatus, or a warning sound is emitted.

The developing device of the present embodiment uses the developer 850
This is a batch supply type in which g supply is performed, and the target remaining developer amount at the time of the developer absence determination is 200 g.

In the developing device having the above configuration, an image is output and the developer is consumed, the developer remaining amount detecting member 13 outputs a no-developer signal, and the developer remaining amount determining device 14 determines that there is no developer. At this point, the image output was stopped, and the measurement of the amount of the remaining developer in the developing container and the observation of the remaining developer in the developing container were performed a plurality of times. As a result, the developer remaining amount determination device 14 does not use the developer without the occurrence of an abnormally charged image of the developer due to an excessive amount of the developer in the developing chamber 3, the deterioration of the developer due to packing, or the image omission due to the lack of the developer. A good image could be output until the output was stopped. In addition, the fluctuation width of the remaining developer amount is as small as 200 ± 10 g, and highly accurate detection can be performed.
In the developing room 3, the lines from the line a to the line b remained,
In the first hopper chamber 5 and the second hopper chamber 7, only about 3 mm remains from the bottom of the developing container. In a state where sufficient developer is left in the developing chamber 3, the total amount of remaining developer is minimized. I was able to.

[Second Embodiment] Next, a developing device according to a second embodiment of the present invention will be described in detail with reference to FIG. FIG. 3 is a schematic sectional view of a developing device according to the second embodiment of the present invention. Note that members having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 3, the developer remaining amount detecting member 13 is disposed in the first hopper chamber 5 adjacent to the developing chamber 3. The developer remaining amount detecting member 13 is
Approximately 15 m from the bottom of the developing container, near the inner wall of the hopper chamber 5
It is arranged so that the position of m is the center. The sensor surface of the developer remaining amount detecting member 13 has a circular shape with a diameter of 10 mm, and the developer is present in all regions on the sensor surface since the developer is not present in a half or more region on the sensor surface. A signal indicating that there is no developer is output in one of the states where no developer exists. In other words, the output of the signal indicating no developer is started during the period from the state in which the amount of the developer decreases to the line a in FIG. 3 to the state in which the amount of the developer decreases to the line b.

Incidentally, based on the signal indicating that there is no developer, the user is prompted to supply the developer to the developing device. Specifically, for example, although not shown, the fact is displayed on a display unit or the like of an operation panel on the upper surface of the apparatus, or a warning sound is emitted.

The developing device of the present embodiment uses the developer 850
This is a collective replenishment type in which g is supplied, and the target remaining developer amount at the time of determination that there is no developer is 230 g.

In the developing device having the above configuration, an image is output and the developer is consumed, the developer remaining amount detecting member 13 outputs a no-developer signal, and the developer remaining amount determining device 14 determines that there is no developer. At this point, the image output was stopped, and the measurement of the amount of the remaining developer in the developing container and the observation of the remaining developer in the developing container were performed a plurality of times. As a result, the developer remaining amount determination device 14 does not use the developer without the occurrence of an abnormally charged image of the developer due to an excessive amount of the developer in the developing chamber 3, the deterioration of the developer due to the packing, or the image omission due to the lack of the developer. A good image could be output until the output was stopped. In addition, the fluctuation width of the remaining developer amount is as small as 230 ± 20 g, and highly accurate detection can be performed.
In the developing chamber 3 and the first hopper chamber 5, a line a to a line b
However, only about 3 mm from the bottom of the developing container remains in the second hopper chamber 7, and a sufficient amount of the developer is left in the developing chamber 3. I was able to.

Third Embodiment Next, a developing device according to a third embodiment of the present invention will be described in detail with reference to FIG. FIG. 4 is a schematic sectional view of a developing device according to a third embodiment of the present invention. Note that members having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 4, a partition wall 9 'between the developing chamber 3 and the first hopper chamber 5 and the first
Partition wall 10 'between hopper chamber 5 and second hopper chamber 7
Are formed along the locus of rotation of the first rotary stirring member 6 and the locus of rotation of the second rotary stirring member 8, respectively.

In the developing device having the above-described structure, the same examination as in the first embodiment was performed. As a result, an abnormally charged image of the developer due to an excessive amount of the developer in the developing chamber 3, the deterioration of the developer due to packing, or the developer A good image could be output without the occurrence of image omission due to lack, and until the developer remaining amount determination device 14 determined that there was no developer and stopped the output. The fluctuation width of the remaining developer amount is 200 ± 5.
g, which is very small and can perform highly accurate detection, and the remaining developer in the developing container remains from the line a to the line b in the developing chamber 3, but the first hopper chamber 5 and the second hopper chamber 7
Only about 1 mm remains from the bottom of the developer container.
With a sufficient amount of developer remaining in the developing chamber 3, the total amount of remaining developer could be minimized.

[0048]

As described above, according to the present invention,
The partition between two adjacent hopper chambers is a wall-shaped partition having a height lower than the rotation center of the rotary stirring member in the hopper chamber on the upstream side in the developer transport direction, and the partition between the developing chamber and the hopper chamber is formed. By forming a partition having a slit-shaped opening in a wall on one side, packing of the developer in the developing chamber does not occur, and the necessary and sufficient amount of the developer for the developing chamber and the developer carrying member is provided. Can be supplied.

Further, in the developing chamber or the hopper chamber,
By providing at least one developer remaining amount detection member, highly accurate detection can be performed at the time of replenishment of the developer, and at the same time, sufficient developer is left to be supplied to the developer carrier. The amount of residual developer can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a developing device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of an image forming apparatus provided with a developing device according to the present invention.

FIG. 3 is a schematic sectional view of a developing device according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view of a developing device according to a third embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional developing device.

[Explanation of symbols]

 a ... line b ... line 1 ... developer carrier 2 ... latent image carrier 3 ... developing chamber 4 ... developing chamber stirring member 5 ... first hopper chamber 6 ... first rotary stirring member 7 ... second hopper chamber 8 ... second 2 rotation stirring member 9 ... partition wall 9 '... partition wall 9a ... opening 10 ... partition wall 10' ... partition wall 11 ... developer regulating member 12 ... opening 13 ... developer remaining amount detecting member 14 ... developer remaining amount determining device Reference Signs List 22 charging means 23 exposure means 24 developing device 25 transfer means 26 cleaning means 27 fixing means 28 transport path

Claims (9)

[Claims] 1. A developing chamber having a developer carrier for transporting a developer to an image carrier, and a rotary agitator for containing the developer and transporting the developer to the developing chamber or an adjacent hopper chamber while agitating the developer. A developing device having at least two or more hopper chambers each having a member, wherein the developing chamber and the hopper chamber are all communicated with each other and partitioned by partitions. A wall-shaped partition having a height lower than the rotation center of the rotary stirring member in the upstream hopper chamber for transporting the developer from the upstream hopper chamber to the downstream hopper chamber in the developer transport direction; The partition between the chamber and the hopper chamber is a partition having a slit-like opening in one wall. 2. The apparatus according to claim 1, wherein the slit-shaped opening of the partition between the developing chamber and the hopper chamber is located at a position lower than the center of rotation of a rotary stirring member in the hopper chamber adjacent to the developing chamber. 3. The developing device according to claim 1. 3. The developing device according to claim 1, wherein a developer remaining amount detecting member is provided in at least one of the developing chamber and the hopper chamber. 4. The developing device according to claim 1, wherein a developer remaining amount detecting member is provided in a hopper chamber adjacent to the developing chamber. 5. The developing device according to claim 3, wherein the developer detecting member has a piezoelectric element. 6. The method according to claim 1, wherein a shape of a wall partitioning between adjacent hopper chambers is a shape along a rotation locus of a rotary stirring member of each hopper chamber. Developing device. 7. An image forming apparatus having an image carrier and a process unit acting on the image carrier, and forming an image on a recording medium, wherein the process unit is any one of claims 1 to 7. An image forming apparatus, comprising the developing device according to item 9. 8. The image forming apparatus according to claim 7, wherein the image forming apparatus has means for urging a user to replenish the developer to the developing device based on a detection result of the developer remaining amount detecting member. Image forming apparatus. 9. The image forming apparatus according to claim 7, wherein the one replenishment of the developer to the developing device is a large amount replenishment of 500 g or more at a time.